A genotyping of a new avian infectious bronchitis virus isolated from chickens proventriculus in Egypt
A genotyping of a new avian infectious bronchitis virus isolated from chickens proventriculus in Egypt
Ehab M. El-Nahas1, Hemat S. El-Sayed2, Sawsan S. El-Basuni3, Gabr F. El-Bagoury1
ABSTRACT
Background: A novel avian infectious bronchitis virus (IBV), Egypt/Qal/014p was isolated from 14-day-old broiler chickens with proventriculitis in Qaluobia province of Egypt in 2014. Objective: The isolate was identified by a real time RT-PCR targeting the nucleocapsid (N) gene with further genetic and antigenic characterization. Methods: Beside a real time RT-PCR; sequence analysis of partial S1 gene, cross-neutralization and the challenge experiment for H120 vaccinated broiler chickens were also performed. Results: Egypt/Qal/014p had close relation with that of the Massachusetts prototypes. Comparisons nucleotide and amino acid sequence of partial S1 gene showed that the recent isolate had 98.2% and 95.2% nucleotide similarities and 96.8% and 91.4% amino acid similarities with the commonly used IBV vaccine Massachusetts strains H120 and M41 respectively. Egypt/Qal/014p had a unique amino acid substitution at residues 39 (Serine), 40 (Tyrosine), 41 (Lysine), 64 (Glutamate) and 69 (Valine) of the S1 proteins from H120 and M41.The cross-neutralization test revealed antigenic relatedness of Egypt/Qal/014p with Massachusetts serotypes. The commercial H120 vaccine conferred partial protection against proventriculitis induced by Egypt/Qal/014p. Conclusion: IBV strains exhibiting proventriculitis were found co-circulating in broiler chickens in Egypt and optimum control of IBV in Egypt require preparation of vaccine from indigenous isolates beside periodic evaluation of cross-protective capabilities of such vaccine.
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